Showing papers on "Handover published in 1985"
Patent•
9 Jul 1985TL;DR: In this paper, a data message transmission system for a cellular radiotelephone system provides protection against data loss caused by multipath fade and subscriber unit handoff by halting the data transmission prior to handoff and resuming data transmission after handoff.
Abstract: A data message transmission system for a cellular radiotelephone system provides protection against data loss caused by multipath fade and subscriber unit handoff. Data from data terminal equipment (801) to be transmitted is converted by a system data processor (805) and radio signalling interface (807) into a format compatible with radio transmission prior to transmission by a transceiver (809). The data is reconverted to its original format following reception. Handoff is accomplished by halting the data transmission prior to handoff and resuming data transmission after handoff. Call supervision occurs via busy-idle bit coding performed in radio signalling interface (807).
232 citations
Patent•
NEC1
TL;DR: In this article, a multi-direction time division multiplex (MIMO) communications network with a plurality of scattered satellite stations and one central station is considered, where the central station produces a control signal for each satellite station and sends it to the satellite station.
Abstract: A space diversity communications system usable with a multi-direction time division multiplex communications network which consists of a plurality of scattered satellite stations and one central station. While the central station is provided with a single antenna, each satellite station is provided with two antennas, main and supplementary. The central station, responsive to received signal, produces a control signal for each satellite station and sends it the satellite station. The satellite station selects either of two antennas in response to the control signal, thereby increasing radio transmission quality on a satellite-by-satellite basis.
36 citations
21 May 1985
TL;DR: A detailed and accurate simulation of the interaction of handoff and power-level control algorithms with a variable and sometime hostile environment is developed that is used in studies to show that adjacent channel interference is a significant but not dominant impairment in large-cell and small-cell cases.
Abstract: Cellular system performance depends on the interaction of handoff and power-level control algorithms with a variable and sometime hostile environment. We have developed a detailed and accurate simulation of this process that can used to evaluate a particular system's configuration and predict signal-to-impairment levels, blocking, cutoff calls, and many other performance items. We have used it in studies to show that adjacent channel interference is a significant but not dominant impairment in large-cell and small-cell cases, and that dynamic power-control algorithms are effective in controlling cutoff calls, even in the face of Rayleigh-fading induced measurement error.
19 citations
21 May 1985
TL;DR: In this article, the authors analyze the performance of cellular systems under both noise-limited and interference-limited service conditions, concentrating on cellsite-to-mobile voice-channel links.
Abstract: For both noise-limited and interference-limited service, a propagation and system performance analysis asks: (1) What are the locations, sizes and importance of "dead spots" in cellular system coverage for each of various service functions such as call setup, handoff and call termination? (2) During the busiest hour of an average business day, is each channel nearly fully loaded or else critical for the protection of life and property or for proper operation of the system? This paper discusses ideas for analyzing the performance of cellular systems under (1) above, concentrating on cellsite-to-mobile voice-channel links. Situations are emphasized where good estimates of propagation uncertainty are especially useful for choosing between preliminary analysis and immediate implementation or upgrading of an overall plan. Satisfactory telephone system engineering is assumed.